U.S. patent application number 11/086232 was filed with the patent office on 2006-03-30 for apparatus and method for generating parallax image.
Invention is credited to Rieko Fukushima, Yuzo Hirayama, Tatsuo Saishu, Kazuki Taira, Yasunobu Yamauchi, Shingo Yanagawa.
Application Number | 20060066718 11/086232 |
Document ID | / |
Family ID | 36098569 |
Filed Date | 2006-03-30 |
United States Patent
Application |
20060066718 |
Kind Code |
A1 |
Yanagawa; Shingo ; et
al. |
March 30, 2006 |
Apparatus and method for generating parallax image
Abstract
An apparatus for generating a parallax image to be used for a
display of a three-dimensional image on a three-dimensional
integral imaging display includes an image signal acquiring unit,
an image signal assigning unit, and a parallax image generator. The
image signal acquiring unit acquires a plurality of image signals
by picking up an image of an image object from a plurality of
different parallax directions. The image signal assigning unit
assigns an output order of the plurality of image signal so that
the plurality of image signals are arranged in a reverse parallax
direction order to an order of beam directions of the
three-dimensional integral imaging display. The parallax image
generator generates a parallax image from the plurality of image
signals to which an output order is assigned by the image signal
assigning unit.
Inventors: |
Yanagawa; Shingo; (Kanagawa,
JP) ; Yamauchi; Yasunobu; (Kanagawa, JP) ;
Taira; Kazuki; (Tokyo, JP) ; Fukushima; Rieko;
(Tokyo, JP) ; Saishu; Tatsuo; (Tokyo, JP) ;
Hirayama; Yuzo; (Kanagawa, JP) |
Correspondence
Address: |
FINNEGAN, HENDERSON, FARABOW, GARRETT & DUNNER;LLP
901 NEW YORK AVENUE, NW
WASHINGTON
DC
20001-4413
US
|
Family ID: |
36098569 |
Appl. No.: |
11/086232 |
Filed: |
March 23, 2005 |
Current U.S.
Class: |
348/51 ; 348/42;
348/E13.015; 348/E13.028; 348/E13.029; 348/E13.043 |
Current CPC
Class: |
H04N 13/351 20180501;
H04N 13/307 20180501; H04N 13/243 20180501; H04N 13/305
20180501 |
Class at
Publication: |
348/051 ;
348/042 |
International
Class: |
H04N 13/04 20060101
H04N013/04; H04N 13/00 20060101 H04N013/00; H04N 15/00 20060101
H04N015/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 29, 2004 |
JP |
2004-285243 |
Claims
1. An apparatus for generating a parallax image to be used for a
display of a three-dimensional image on a three-dimensional
integral imaging display, comprising: an image signal acquiring
unit that acquires a plurality of image signals by picking up an
image of an image object from a plurality of different parallax
directions; an image signal assigning unit that assigns an output
order of the plurality of image signal so that the plurality of
image signals are arranged in a reverse parallax direction order to
an order of beam directions of the three-dimensional integral
imaging display; and a parallax image generator that generates a
parallax image from the plurality of image signals to which an
output order is assigned by the image signal assigning unit.
2. The apparatus according to claim 1, wherein the image signal
assigning unit assigns parallax identification information for
identifying each parallax direction to the plurality of image
signals obtained from the image signal acquiring unit in a reverse
order of the order of the parallax directions in the image signal
acquiring unit; and the parallax image generator generates the
parallax image from the plurality of image signals to which the
parallax identification information is assigned in the reverse
order of the order of the parallax directions by the image signal
assigning unit.
3. The apparatus according to claim 1, further comprising an image
storing unit that stores the parallax image, wherein the parallax
image generator further stores the generated parallax image in the
image storing unit.
4. The apparatus according to claim 2, further comprising an image
storing unit that stores the parallax image, wherein the parallax
image generator further stores the generated parallax image in the
image storing unit.
5. The apparatus according to claim 1, wherein the image signal
assigning unit, in response to an instruction of reverse order
assignment, assigns the output order of the plurality of image
signals so that the plurality of image signals acquired from the
image signal acquiring unit is arranged in a reverse order of an
order of beam directions of the three-dimensional integral imaging
display.
6. The apparatus according to claim 2, wherein the image signal
assigning unit, in response to an instruction of reverse order
assignment, assigns the output order of the plurality of image
signals so that the plurality of image signals acquired from the
image signal acquiring unit is arranged in a reverse order of an
order of beam directions of the three-dimensional integral imaging
display.
7. The apparatus according to claim 3, wherein the image signal
assigning unit, in response to an instruction of reverse order
assignment, assigns the output order of the plurality of image
signals so that the plurality of image signals acquired from the
image signal acquiring unit is arranged in a reverse order of an
order of beam directions of the three-dimensional integral imaging
display.
8. The apparatus according to claim 5, further comprising an image
signal storing unit that stores the plurality of image signals
acquired by the image signal acquiring unit, wherein the image
signal assigning unit, in response to an instruction of reverse
order assignment, assigns the output order of the plurality of
image signals so that the plurality of image signals stored in the
image signal storing unit are arranged in a reverse parallax
direction order of the order of the beam directions of the
three-dimensional integral imaging display.
9. The apparatus according to claim 6, further comprising an image
signal storing unit that stores the plurality of image signals
acquired by the image signal acquiring unit, wherein the image
signal assigning unit, in response to an instruction of reverse
order assignment, assigns the output order of the plurality of
image signals so that the plurality of image signals stored in the
image signal storing unit are arranged in a reverse parallax
direction order of the order of the beam directions of the
three-dimensional integral imaging display.
10. The apparatus according to claim 7, further comprising an image
signal storing unit that stores the plurality of image signals
acquired by the image signal acquiring unit, wherein the image
signal assigning unit, when the reverse order assignment is
instructed, assigns the output order of the plurality of image
signals so that the plurality of image signals stored in the image
signal storing unit are arranged in a reverse parallax direction
order of the order of the beam directions of the three-dimensional
integral imaging display.
11. The apparatus according to claim 1, wherein the image signal
acquiring unit acquires the plurality of image signals from the
plurality of different parallax directions with respect to the
image object arranged in one of an area in front of a point of
regard up to a protrusion limit and an area deeper than the point
of regard up to a depth limit.
12. The apparatus according to claim 2, wherein the image signal
acquiring unit acquires the plurality of image signals from the
plurality of different parallax directions with respect to the
image object arranged in one of an area in front of a point of
regard up to a protrusion limit and an area deeper than the point
of regard up to a depth limit.
13. The apparatus according to claim 3, wherein the image signal
acquiring unit acquires the plurality of image signals from the
plurality of different parallax directions with respect to the
image object arranged in one of an area in front of a point of
regard up to a protrusion limit and an area deeper than the point
of regard up to a depth limit.
14. The apparatus according to claim 5, wherein the image signal
acquiring unit acquires the plurality of image signals from the
plurality of different parallax directions with respect to the
image object arranged in one of an area in front of a point of
regard up to a protrusion limit and an area deeper than the point
of regard up to a depth limit.
15. The apparatus according to claim 8, wherein the image signal
acquiring unit acquires the plurality of image signals from the
plurality of different parallax directions with respect to the
image object arranged in one of an area in front of a point of
regard up to a protrusion limit and an area deeper than the point
of regard up to a depth limit.
16. A method of generating a parallax image to be used for a
display of a three-dimensional image on a three-dimensional
integral imaging display, comprising: acquiring a plurality of
image signals by picking up an image of an image object from a
plurality of different parallax directions; assigning an output
order of the plurality of image signal so that the plurality of
image signals are arranged in a reverse parallax direction order to
an order of beam directions of the three-dimensional integral
imaging display; and generating a parallax image from the plurality
of image signals to which an output order is assigned.
17. A computer program product having a computer readable medium
including programmed instructions for generating a parallax image
to be used for a display of a three-dimensional image on a
three-dimensional integral imaging display, wherein the
instructions, when executed by a computer, cause the computer to
perform: acquiring a plurality of image signals by picking up an
image of an image object from a plurality of different parallax
directions; assigning an output order of the plurality of image
signal so that the plurality of image signals are arranged in a
reverse parallax direction order to an order of beam directions of
the three-dimensional integral imaging display; and generating a
parallax image from the plurality of image signals to which an
output order is assigned.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is based upon and claims the benefit of
priority from the prior Japanese Patent Application No. 2004-285243
filed on Sep. 29, 2004; the entire contents of which are
incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1) Field of the Invention
[0003] The present invention relates to an apparatus for and a
method of generating a parallax image to be used for a display of a
three-dimensional image on a three-dimensional integral imaging
display, and a computer program product which makes a computer
execute the method.
[0004] 2) Description of the Related Art
[0005] Conventionally, as a technique for displaying a
three-dimensional image with a two-dimensional display element,
integral imaging (also called as integral photography) is known
(see, for example, H. Hoshino, F. Okano, H. Isono and I. Yuyama
"Analysis of resolution limitation of integral photography", J.
Opt. Soc. Am, A15 (1998) 2059-2065). According to the integral
imaging, an optical image selecting unit synthesizes and displays
images obtained from a plurality of directions of visual lines on
an image display screen, and allows a selective image viewing
depending on a position of viewpoint of a viewer.
[0006] In particular, as the optical image selecting unit, a beam
directing unit constituted from slits, pin holes, or a lens array
(lenticular lenses, for example) is used. The beam directing unit
limits the pixels viewable from the viewpoint of the viewer. The
beam directing unit and the display element are arranged in a
proper geometrical dimension and a relative position and unit
information corresponding to a direction of light beam that is
emitted from each pixel provided on the display unit and passes
through an aperture of the beam directing unit is assigned to the
pixel, in order to achieve a three-dimensional image display which
includes image information obtained from various viewpoints.
[0007] Here, the three-dimensional image can be defined as an image
including a plurality of images each obtained from a certain
viewpoint in a certain direction. Hereinbelow, an image obtained by
viewing from a certain viewpoint in a predetermined direction is
called a viewpoint image. A three-dimensional image achieved by the
integral imaging is a display image where a plurality of viewpoint
images are combined on unit information basis and spatially
disposed.
[0008] Thus, the three-dimensional integral imaging display
provides a three-dimensional image to the viewer by reproducing a
plurality of light beams from different directions around the
display.
[0009] Such a three-dimensional integral imaging display is
desirable in that the display allows a precise display of different
images depending on a position from which the viewer observes a
display object, since the display reproduces the light beams around
the display. According to the technique, however it is difficult to
provide a three-dimensional image independent of the light beams at
the time of the object image acquisition; for example, it is
difficult to display a three-dimensional image which appears to be
located in the same direction regardless of the position of the
viewer of the display.
[0010] When a parallax image obtained by image pick-up of the image
object from one direction is assigned to all parallax components,
the three-dimensional integral imaging display can display an image
which appears to be in the same direction regardless of the
viewpoint of the viewer of the display. Such an image, however is a
planar image, that is, non-three-dimensional image, which does not
cause binocular parallax of the viewer. Multi-lens stereoscopic
displays employ a parallax barrier or a lenticular lens to assign a
different three-dimensional image to each eye of the viewer as a
right-eye-image or a left-eye-image. Hence, when two images
respectively for a right and a left eyes are input to the display
based on an estimated eye separation, the viewer can observe a
three-dimensional image that appears to be in the same direction
regardless of the viewer's viewpoint as far as the viewer is in an
area which allows observation according to the specification of the
display.
[0011] According to the three-dimensional integral imaging display,
however, parallax components in a viewing area need to be
continuous. When parallax components are arranged alternately for
the right eye and the left eye as in the multi-lens stereoscopic
display mentioned above for the generation of multi-parallax image,
the parallax components are not continuous and a resulting
three-dimensional image appears to be blurred or overlapped.
SUMMARY OF THE INVENTION
[0012] It is an object of the present invention to at least solve
the problems in the conventional technology.
[0013] An apparatus for generating a parallax image to be used for
a display of a three-dimensional image on a three-dimensional
integral imaging display, according to one aspect of the present
invention, includes an image signal acquiring unit that acquires a
plurality of image signals by picking up an image of an image
object from a plurality of different parallax directions; an image
signal assigning unit that assigns an output order of the plurality
of image signal so that the plurality of image signals are arranged
in a reverse parallax direction order to an order of beam
directions of the three-dimensional integral imaging display; and a
parallax image generator that generates a parallax image from the
plurality of image signals to which an output order is assigned by
the image signal assigning unit.
[0014] A method of generating a parallax image to be used for a
display of a three-dimensional image on a three-dimensional
integral imaging display, according to another aspect of the
present invention, includes acquiring a plurality of image signals
by picking up an image of an image object from a plurality of
different parallax directions; assigning an output order of the
plurality of image signal so that the plurality of image signals
are arranged in a reverse parallax direction order to an order of
beam directions of the three-dimensional integral imaging display;
and generating a parallax image from the plurality of image signals
to which an output order is assigned.
[0015] The computer program product according to still another
aspect of the present invention causes a computer to perform the
method according to the present invention.
[0016] The other objects, features, and advantages of the present
invention are specifically set forth in or will become apparent
from the following detailed description of the invention when read
in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 is a block diagram of a structure of an image
generating apparatus according to a first embodiment;
[0018] FIG. 2 is a flowchart of a generating process of a parallax
image;
[0019] FIG. 3 is an explanatory diagram of a display area of a
three-dimensional integral imaging display;
[0020] FIG. 4 is a flowchart of an image signal assigning
process;
[0021] FIG. 5 is an explanatory diagram of a content of a frame
buffer storing parallax numbers and image signals in association
with each other upon input from an image signal acquiring unit 101,
and a content of a frame buffer storing parallax numbers and image
signals in association with each other after an order change of the
parallax numbers into reverse;
[0022] FIG. 6 is an explanatory diagram of light beams output from
a conventional three-dimensional integral imaging display and a
three-dimensional image observed from each viewer's direction;
[0023] FIG. 7 is an explanatory diagram of light beams output from
the three-dimensional integral imaging display based on a generated
parallax image and a three-dimensional image observed from each
viewer's direction according to the first embodiment;
[0024] FIG. 8 is a block diagram of a structure of an image
generating apparatus according to a modification of the first
embodiment;
[0025] FIG. 9 is a block diagram of a structure of an image
generating apparatus according to a second embodiment; and
[0026] FIG. 10 is a flowchart of a generating process of a parallax
image.
DETAILED DESCRIPTION
[0027] Exemplary embodiments of an apparatus, a method and a
computer program for image generation according to the present
invention will be explained in detail below with reference to the
accompanying drawings.
[0028] An image generating apparatus according to a first
embodiment assigns a plurality of image signals obtained by image
pick-up of an image object from a plurality of different parallax
directions in a reverse order from an order of directions of light
beams output from a three-dimensional integral imaging display
(hereinafter also referred to simply as a stereoscopic display
device).
[0029] FIG. 1 is a block diagram of a structure of the image
generating apparatus according to the first embodiment The image
generating apparatus according to the first embodiment includes an
image signal acquiring unit 101, an image signal assigning unit
102, and a parallax image generator 103, and is connected to a
stereoscopic display device 104 as shown in FIG. 1.
[0030] The image signal acquiring unit 101 includes a plurality of
cameras 0 to n-1 that pick up images of the image object from
different viewpoints and acquires the images picked up by the
respective cameras as image signals to supply to the image signal
assigning unit 102.
[0031] The plurality of cameras 0 to n-1 are arranged in a
horizontal direction with respect to the image object so that each
camera picks up the image thereof from different parallax
direction, thereby providing a multi-viewpoint image. Parallax
numbers 0 to n-1 are assigned in an ascending order to image
signals provided from the left-end camera 0 to the right-end camera
n-1 to designate the parallax directions of the image signals from
the respective cameras 0 to n-1.
[0032] The image signals are generated according to a known
technique. Particularly, a viewpoint that serves as an image pick
up position of the camera is set to determine a base plane of the
image pick-up. Then a point of regard is set on the base plane. The
viewpoint of the camera corresponds to the viewpoint of the viewer
and the point of regard corresponds to a center of a screen of the
stereoscopic display device 104. The cameras 0 to n-1 are arranged
towards the base plane so that the base plane is aligned with a
position of pupil of a beam directing unit and the image-pick up is
conducted.
[0033] According to the embodiment, the image object is arranged
either in an area in front of the point of regard up to a
protrusion limit or in an area deeper than the point of regard up
to a depth limit for the image pick-up by the cameras 0 to n-1.
Details of such arrangement of the image object are explained
later.
[0034] According to the embodiment, the cameras 0 to n-1 are
employed for the acquisition of the image signals. The image
signals, however, may be acquired through rendering by a virtual
camera in a three-dimensional (3D) model space. The rendering is a
process of image data drawing on a two-dimensional screen. In the
rendering, the virtual camera and the point of regard are set. The
virtual camera is a hypothetical camera arranged in a position
determined corresponding to a light beam that is output from the
stereoscopic display device, and arranged in front of a display
panel of the stereoscopic display device 104 so that the virtual
camera faces the center of the display panel. The point of regard
is set in the center of the display panel.
[0035] The image signal assigning unit 102 receives image signals
of the respective cameras 0 to n-1 from the image signal acquiring
unit 101 to output the received image signals to the parallax image
generator 103 in reverse order. In other words, the image signal
assigning unit 102 assigns the image signals received from the
image signal acquiring unit 101 in a reverse order from the order
of directions of the light beams output from the stereoscopic
display device 104.
[0036] In particular, when the parallax numbers of the image
signals are designated by 0 to n-1 corresponding to the cameras 0
to n-1, as shown in FIG. 1, when the image signals are output from
the image signal assigning unit 102 to the parallax image generator
103, the image signals are assigned in the order of parallax
numbers n-1 to 0. Then, the image signals from the respective
cameras are in reverse order of the directions of light beams
output from the stereoscopic display device 104.
[0037] In a conventional image generating apparatus, the image
signals from the respective cameras are assigned in the same order
with the directions of light beams output from the stereoscopic
display device 104 for the generation of the parallax image. In the
image generating apparatus 100 according to the first embodiment,
however, the image signals from the respective cameras are assigned
in reverse order from the directions of light beams output from the
stereoscopic display device 104, in order to allow stereoscopic
display device 104 to exhibit an image which appears to be in the
same direction regardless of the viewer's position.
[0038] The parallax image generator 103 receives a plurality of
image signals to which the parallax numbers are assigned in reverse
order from the parallax numbers of the image signals as output from
the cameras, to generate the parallax image constituting a
three-dimensional image of the image object.
[0039] The stereoscopic display device 104 displays a
three-dimensional image according to the integral imaging
technique. The stereoscopic display device 104 includes a display
element (not shown) that forms an image from a plurality of pixel
dots arranged in a two-dimensional manner and a beam directing unit
(not shown) that limits the direction of light beams emitted from
the pixel dots to limit a visual angle in the horizontal
direction.
[0040] As the stereoscopic display device 104, a flat panel where
pixel dots are arranged in a matrix is more preferable than a
cathode-ray tube (CRT) or a projector, since misalignment of the
pixel dots exerts a significant negative influence on the direction
of light beam emission. Such a flat panel is, for example, a
non-luminous liquid crystal display (LCD) panel, a luminous plasma
display panel (PDP), or an organic electroluminescence (EL) panel.
As the beam directing unit, lenticular lenses having a bus line in
a direction perpendicular to the screen, or slits may be employed.
Since the beam direction is limited to the direction horizontal to
the screen, each bus line of the lenticular lens or each aperture
of the slit does not necessarily be in a straight line shape
arranged over the vertical direction of the screen and may be in a
line or a dotted line shape as suitable for the pixel dot
arrangement.
[0041] In addition, in the integral imaging stereoscopic display
device 104 according to the embodiment, though there is no specific
condition to be satisfied with respect to the beam direction, the
pitch of the beam directing unit is set to an integral multiple of
the pitch of the pixel dots, i.e. set equal to the pitch of a pixel
group constituted from several pixel dots, in order to form a group
of parallel beams to achieve an efficient generation of parallax
image in practice.
[0042] The display of the three-dimensional image by the
stereoscopic display device 104 is performed in the same manner as
in the conventional stereoscopic display device.
[0043] A generating process of the parallax image in the image
generating apparatus 100 according to the embodiment is explained
next. FIG. 2 is a flowchart of the generating process of the
parallax image.
[0044] First, the image signal acquiring unit 101 picks up the
image of the image object from various parallax directions by the
cameras 0 to n-1 and acquires the image signals of the cameras 0 to
n-1, designated by the parallax numbers 0 to n-1, respectively, to
output the acquired image signals to the image signal assigning
unit 102 (at step S201).
[0045] Here, the image signal assigning unit 102 assigns the
parallax numbers 0 to n-1 in reverse order from the order of beam
directions output from the integral imaging stereoscopic display
device 104 to the image signals, which are supplied from the
cameras 0 to n-1 each pick up the image of the image object from
different viewpoint, in order to achieve the display of an image
that appears to be in the same direction regardless of the viewer's
viewpoint on the stereoscopic display device 104. Such processing,
however, may cause the following inconvenience.
[0046] When the signals are processed as described above, the image
picked up from the left side of the image object is observed by the
right eye of the viewer, while the image picked up from the right
side of the image object is observed by the left eye of the viewer.
This phenomenon is called a reverse viewing or a reverse
stereoscopic viewing. In the reverse viewing, a part of the image
object located at a deeper position than the point of regard
appears to be located at a shallower position, while a part of the
image object located at a shallower position than the point of
regard appears to be located at a deeper position. Hence, the
viewer cannot correctly perceive the contour of the surface of the
image object. To suppress the inconvenient effect, in the
embodiment, the image object is placed either in an area in front
of the point of regard up to the protrusion limit or in an area
deeper than the point of regard up to the dept limit, and the
cameras 0 to n-1 are employed for the image pick-up. Thus the
inconsistency of the depth perception in the reverse viewing is
alleviated.
[0047] FIG. 3 is an explanatory diagram of a display area of the
integral imaging stereoscopic display device 104. In FIG. 3, the
image object is arranged either in an area A in front of the point
of regard up to the protrusion limit or in an area B deeper than
the point of regard up to the depth limit, and the cameras 0 to n-1
are employed for the image pick-up.
[0048] Return to FIG. 2, after the image signal acquiring unit 101
outputs the respective image signals to the image signal assigning
unit 102 at the step 201, the image signal assigning unit 102
receives the image signals with the parallax numbers 0-n-1 from the
image signal acquiring unit 101 and temporarily stores the received
image signals with parallax numbers 0 to n-1 in a frame buffer in
association with the respective parallax numbers (at step S202).
Then, the image signal assigning unit 102 changes the parallax
numbers 0 to n-1 of the image signals in the frame buffer to the
reverse order, i.e., to the order of n-1 to 0 (at step S203). Then,
the image signal assigning unit 102 outputs the respective image
signals with the parallax numbers in reverse order to the parallax
image generator 103 (at step S204). Details of the assigning
process of the image signals at the step S203 are explained
later.
[0049] Next, the parallax image generator 103 receives the
respective image signals with the parallax numbers in reverse order
from the image signal assigning unit 102 to generate the parallax
image from the respective image signals with the parallax numbers 0
to n-1 (at step S205).
[0050] Next, the image signal assigning process by the image signal
assigning unit 102 at the step S203 is explained. FIG. 4 is a
flowchart of the image signal assigning process. Hereinbelow, an
image signal with a parallax number p upon reception thereof from
the image signal acquiring unit 101 is denoted as an image signal
p.
[0051] In the image signal assigning unit 102, initial values of
parallax numbers p and q are set as p=0, q=n-1 (at step S401).
Here, n-1 denotes the maximum of the parallax number, i.e., the
number of cameras.
[0052] Then, the image signal assigning unit 102 acquires the
parallax number p of the image signal p from the frame buffer (at
step S402). Then, the image signal assigning unit 102 changes the
acquired parallax number p to q, thereby setting the parallax
number of the image signal p to q (at step S403). Then, the image
signal assigning unit 102 increases the value of the parallax
number p by one and decreases the value of the parallax number q by
one (at step S404). The image signal assigning unit 102 determines
whether the parallax number p is larger than the maximum parallax
number n-1 (at step S405). When the parallax number p is determined
to be equal to or smaller than the maximum (No at the step S405),
the image signal assigning unit 102 repeats the process from the
step S402 to the step S404.
[0053] When the parallax number p is determined to be larger than
the maximum parallax number n-1 at the step S405 (Yes at the step
S405), the image signal assigning process ends.
[0054] Thus, the parallax numbers of the image signals are changed
to the reverse order. FIG. 5 is an explanatory diagram of a content
of a frame buffer storing the parallax numbers and the image
signals in association with each other at the reception thereof
from the image signal acquiring unit 101 and a content of a frame
buffer storing the parallax numbers and the image signals in
association with each other after the change of the parallax number
in reverse order. As shown in FIG. 5, before the change, the
parallax numbers 0 to n-1 are assigned to the image signals 0 to
n-1 in order, whereas after the change, the parallax numbers are
reversed and the parallax numbers n-1 to 0 are assigned to the
image signals 0 to n-1, respectively.
[0055] In the conventional image generating apparatus, the image
signals from the respective cameras are assigned in an order of the
beam directions output from the stereoscopic display device 104 to
generate the parallax image and to display the three-dimensional
image on the stereoscopic display device. Hence, as shown in FIG.
6, it is possible to display different three-dimensional images
according to the viewing positions of the viewers, such as a viewer
A and a viewer B. However it is not possible to display a
three-dimensional image which appears to be the same regardless of
the difference in viewer's position and direction of viewpoint, as
in the case of viewers C and D shown in FIG. 7.
[0056] In the image generating apparatus 100 according to the first
embodiment, since the respective image signals output from the
cameras 0 to n-1 of the image signal acquiring unit 101 are
assigned in a reverse order of the beam directions output from the
stereoscopic display device 104, the integral imaging stereoscopic
display device 104 can provide a three-dimensional image that
appears to be in the same direction so that the viewer feels as if
he/she observes the image object from the same direction even when
he/she moves to a different position.
[0057] Though in the embodiment, the assigning process by the image
signal assigning unit 102 is realized through the processing by
software, the process may be realized with a hardware including a
unit for assigning the respective received image signal inputs in a
reverse order of the parallax directions to provide the outputs to
the parallax image generator 103.
[0058] In addition, though the parallax image generated by the
parallax image generator 103 is directly sent to the stereoscopic
display device 104 for the display of the three-dimensional image
in the embodiment, the parallax image generated by the parallax
image generator 103 may be temporarily stored in a storing unit as
a modification of the first embodiment.
[0059] FIG. 8 is a block diagram of a structure of an image
generating apparatus according to a modification of the first
embodiment. As shown in FIG. 8, an image generating apparatus 800
according to the modification is provided with an image storing
unit 105 that stores the parallax image generated by the parallax
image generator 103. As such image storing unit 105, a recording
medium such as a hard disc drive (HDD) or a memory is used.
[0060] In the image generating apparatus according to the
modification, after the parallax image generator 103 generates the
parallax image from the plurality of image signals with the
parallax numbers assigned in reverse order to the parallax
directions, the image storing unit 105 stores the generated
parallax image. Then, the parallax image stored in the image
storing unit 105 is sent to the stereoscopic display device 104
when a display request from the stereoscopic display device 104 is
received by the image generating apparatus 800.
[0061] In addition, the image storing unit 105 may not be provided
in the image generating apparatus 100. The image storing unit 105
may be connected between the image generating apparatus 800 and the
stereoscopic display device 104 as shown in FIG. 8 so that the
stereoscopic display device 104 reads the parallax image in the
image storing unit 105.
[0062] In the image generating apparatus 100 according to the first
embodiment, when the image signal acquiring unit 101 acquires the
plurality of image signals, the parallax numbers are always
assigned in reverse order to the parallax directions. In an image
generating apparatus according to a second embodiment, the image
signal acquiring unit acquires the plurality of image signals and
dynamically changes the order of the parallax numbers with respect
to the parallax directions according to a switching direction which
indicates either a descending order (reverse order) or an ascending
order (unchanged order).
[0063] FIG. 9 is a block diagram of a structure of an image
generating apparatus 900 according to the second embodiment. The
image generating apparatus 900 according to the second embodiment
includes an image signal acquiring unit 901, an image signal
assigning unit 902, the parallax image generator 103, and an image
signal storing unit 905, and is connected to the stereoscopic
display device 104 as shown in FIG. 9.
[0064] The image signal acquiring unit 901 is provided with the
plurality of cameras 0 to n-1 that pick up the image of the image
object from various viewpoints in the same manner as in the first
embodiment The image signal acquiring unit 901 according to the
second embodiment acquires the images picked up by the respective
cameras as the image signals to store the acquired image signals in
the image signal storing unit 905.
[0065] Here, the plurality of cameras 0 to n-1 are arranged in a
horizontal direction with respect to the image object so that the
cameras pick up the image of the image object from different
viewpoints at different parallax directions as in the first
embodiment. The parallax numbers 0 to n-1 are assigned in ascending
order to the image signals from the respective cameras from the
left-end camera 0 to the right-end camera n-1 in order to designate
the parallax directions of the image signals from the respective
cameras 0 to n-1.
[0066] The image signal storing unit 905 serves to store the
plurality of image signals with the respective parallax numbers
acquired by the image signal acquiring unit 901, and in particular
is a recording medium such as a HDD or a memory.
[0067] The image signal assigning unit 902 acquires the respective
image signals stored in the image signal storing unit 905 and
assigns the image signals of the respective cameras in the same
order or in the reverse order of the image signals to be supplied
to the parallax image generator 103, i.e., the beam directions
output from the stereoscopic display device. Particularly, the
image signal assigning unit 902 receives a switching direction from
a user via an input device (not shown) and, when the switching
direction indicates a reverse order switching, supplies the image
signals of the parallax numbers 0 to n-1 as the image signals with
the parallax numbers n-1 to 0 to the parallax image generator 103
in the same manner as in the first embodiment.
[0068] On the other hand, when the switching direction indicates a
same order switching, the image signal assigning unit 902 supplies
the image signals with the parallax numbers 0 to n-1 to the
parallax image generator 103 without changing the order of the
parallax numbers (i.e. in the same order).
[0069] The parallax image generator 103, similarly to the first
embodiment, receives the plurality of image signals with the
parallax numbers assigned by the image signal assigning unit 902 in
the reverse order from the parallax numbers of the image signals as
received from the respective cameras, to generate the parallax
image constituting the three-dimensional image of the image object.
The stereoscopic display device 104, similarly to the first
embodiment, displays the three-dimensional image according to the
integral imaging technique.
[0070] A generating process of the parallax image by the image
generating apparatus 900 according to the second embodiment is
explained next. FIG. 10 is a flowchart of the generating process of
the parallax image.
[0071] The image signal acquiring unit 901 picks up the images of
the image object from various parallax directions with the
plurality of cameras 0 to n-1 to acquire the image signals of the
parallax numbers 0 to n-1 from the cameras 0 to n-1 (at step
S1001). Then, the image signal acquiring unit 901 stores the
acquired image signals in the image signal storing unit 905 (at
step S1002).
[0072] The image signal assigning unit 902 receives a direction
from a user via an input device (not shown) and determines whether
the received direction is a reverse order switching direction or
not (at step S1003). When the received direction is the reverse
order switching direction (Yes at the step S1003), the image signal
assigning unit 902 acquires the image signals of the parallax
numbers 0 to n-1 from the image signal storing unit 905 and stores
the acquired image signals with the parallax numbers 0 to n-1 in a
frame buffer maintaining the association between the image signals
and the parallax numbers (at step S1004). Then, the image signal
assigning unit 902 changes the parallax numbers 0 to n-1 of the
image signals in the frame buffer to the reverse order, i.e., to
the order of the parallax numbers n-1 to 0 (at step S1005). The
image signal assigning unit 902 supplies the respective image
signals with changed order of parallax numbers to the parallax
image generator 103 (at step S1007). Here, the assigning process of
the image signals at the step S1005 is conducted in the same manner
as in the first embodiment as explained with reference to FIG.
4.
[0073] The parallax image generator 103 receives the respective
image signals with the parallax numbers changed into the reverse
order from the image signal assigning unit 902, to generate the
parallax image from the respective image signals with the parallax
numbers 0 to n-1 (at step S1008).
[0074] When the received direction at the step S1003 is not the
reverse order switching direction, i.e., is a same order switching
direction (No at the step S1003), the image signal assigning unit
902 acquires the image signals of the parallax numbers 0 to n-1
from the image signal storing unit 905 to output the acquired image
signals to the parallax image generator 102 without changing the
order of the parallax numbers (at step S1007).
[0075] Then, the parallax image generator 103 receives the
respective image signals with the parallax numbers in the unchanged
order from the image signal assigning unit 902, to generate the
parallax image from the respective signals with the parallax
numbers 0 to n-1 (at step S1008).
[0076] Thus, in the image generating apparatus 900 according to the
second embodiment, the image signal acquiring unit 901 acquires the
plurality of image signals to temporarily store the image signals
in the image signal storing unit 905 and the order of the parallax
numbers is dynamically switched according to the direction from the
user, i.e. according to the reverse order switching direction or
the same order switching direction. Hence, in the integral imaging
stereoscopic display device 104, it is possible to switch the
three-dimensional image of the image object to be displayed from an
image that appears to be in the same direction regardless of the
viewing direction of the viewer to an image that appears to be
different depending on the viewing direction of the viewer. Thus,
more flexible display of the three-dimensional image can be
achieved.
[0077] The image generating apparatus according to the first or the
second embodiment has a hardware structure utilizing an ordinary
computer and includes a controller such as a central processing
unit (CPU), a storing unit such as a read only memory (ROM) or a
random access memory (RAM), an external storing unit such as a HDD
or a compact disc (CD) drive, a display, and an input unit such as
a keyboard or a mouse.
[0078] An image generating program executed in the image generating
apparatus according to the first or the second embodiment is
recorded in a computer readable recording medium such as a CD-ROM,
a flexible disc (FD), a CD-R, a digital versatile disc (DVD) in the
form of an installable or executable file.
[0079] The image generating program executed in the image
generating apparatus according to the first or the second
embodiment may be stored in a computer connected to a network such
as the Internet, and downloaded via the network. Further, the image
generating program executed in the image generating apparatus of
the first or the second embodiment may be provided or distributed
via a network such as the Internet. Still further, the image
generating program of the first and the second embodiments may be
incorporated into a ROM or the like in advance.
[0080] The image generating program executed by the image
generating apparatus of the first or the second embodiment has a
module structure including above-described units such as the image
signal assigning unit and the parallax generator. In the actual
hardware, the CPU reads out the image generating program from the
recording medium and executes the program to load the respective
units on the main memory thereby generating the image signal
assigning unit, the parallax image generator or the like on the
main memory.
[0081] Additional advantages and modifications will readily occur
to those skilled in the art. Therefore, the invention in its
broader aspects is not limited to the specific details and
representative embodiments shown and described herein. Accordingly,
various modifications may be made without departing from the spirit
or scope of the general inventive concept as defined by the
appended claims and their equivalents.
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